Amortization – Casio ALGEBRA FX2.0 Financial User Manual
Page 13
13
5. Amortization
This calculator can be used to calculate the principal and interest portion of a monthly installment,
the remaining principal, and amount of principal and interest repaid up to any point.
u
uu
u
u
Formula
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b
a
d
e
c
1 2
m
n
a
: interest portion of installment PM1 (
INT
)
b
: principal portion of installment PM1 (
PRN
)
c
: balance of principal after installment PM2 (
BAL
)
d
: total principal from installment PM1 to payment of installment PM2 (
Σ
PRN
)
e
: total interest from installment PM1 to payment of installment PM2 (
Σ
INT
)
*
a
+
b
= one repayment (
PMT
)
a
:
INT
PM1
=
I
BAL
PM1–1
×
i
I
×
(
PMT sign
)
b
:
PRN
PM1
=
PMT
+
BAL
PM1–1
×
i
c
:
BAL
PM2
=
BAL
PM2–1
+
PRN
PM2
d
:
Σ
PRN
=
PRN
PM1
+
PRN
PM1+1
+ … +
PRN
PM2
e
:
Σ
INT
=
INT
PM1
+
INT
PM1+1
+ … +
INT
PM2
PM2
PM1
PM2
PM1
BAL
0
=
PV
(
INT
1
= 0 and
PRN
1
=
PMT
at beginning of installment term)
u
uu
u
u
Converting between the nominal interest rate and effective interest rate
The nominal interest rate (
I
% value input by user) is converted to an effective interest rate (
I
%')
for installment loans where the number of installments per year is different from the number of
compound interest calculation periods.
I%' =
I%
(1 +
)
–1
[
C
/
Y
]
[
P
/
Y
]
100
× [
C
/
Y
]
{ }
×
100
(Number of payments)
Amount of single payment